pl sql case

1SELECT product_id, product_type_id,
2  CASE product_type_id
3    WHEN 1 THEN 'Book'
4    WHEN 2 THEN 'Video'
5    WHEN 3 THEN 'DVD'
6    WHEN 4 THEN 'CD'
7    ELSE 'Magazine'
8  END
9FROM products;

1CASE [ expression ]
2
3   WHEN condition_1 THEN result_1
4   WHEN condition_2 THEN result_2
5   ...
6   WHEN condition_n THEN result_n
7
8   ELSE result
9
10END